Usami I, Kubota M, Bessho R, Kataoka A, Koishi S, Watanabe K, Sawada M, Lin Y W, Akiyama Y, Furusho K
Department of Pediatrics, Faculty of Medicine, Kyoto University, Japan.
Biochem Pharmacol. 1998 Jan 15;55(2):185-91. doi: 10.1016/s0006-2952(97)00429-2.
When a human myeloid cell line, U937, was incubated with etoposide (10 micrograms/mL), morphologically apoptotic cells first appeared at 3 hr and increased with time to 50% at 6 hr. Pretreatment of U937 cells for 30 min with a potent tyrosine kinase inhibitor, herbimycin A (10 microM), significantly suppressed the appearance of apoptotic morphological changes. Concomitantly, herbimycin A pretreatment prevented both high molecular weight and internucleosomal DNA fragmentation induced by etoposide. Two major bands at 30 and 66 kDa with enhanced tyrosine phosphorylation inhibited by herbimycin A were detectable after 30 min of incubation with etoposide. In addition, herbimycin A prevented etoposide-induced NF-kappa B activation. The expressions of Bcl-2 and Bax, on the other hand, were not affected by herbimycin A pretreatment. Herbimycin A was also found to inhibit 1-beta-D-arabinofuranosylcytosine-induced apoptotic changes and NF-kappa B activation. These results suggest that activation of tyrosine kinase(s) may play an important role in apoptotic processes induced by a variety of anti-cancer drugs.
当人髓样细胞系U937与依托泊苷（10微克/毫升）一起孵育时，形态学上的凋亡细胞在3小时时首次出现，并随时间增加，在6小时时达到50%。用强效酪氨酸激酶抑制剂赫曲霉素A（10微摩尔）对U937细胞进行30分钟的预处理，可显著抑制凋亡形态变化的出现。同时，赫曲霉素A预处理可防止依托泊苷诱导的高分子量和核小体间DNA片段化。与依托泊苷孵育30分钟后，可检测到两条主要的酪氨酸磷酸化增强的条带，分别位于30 kDa和66 kDa，且被赫曲霉素A抑制。此外，赫曲霉素A可防止依托泊苷诱导的NF-κB活化。另一方面，赫曲霉素A预处理对Bcl-2和Bax的表达没有影响。还发现赫曲霉素A可抑制1-β-D-阿拉伯呋喃糖基胞嘧啶诱导的凋亡变化和NF-κB活化。这些结果表明，酪氨酸激酶的激活可能在多种抗癌药物诱导的凋亡过程中起重要作用。
